This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-145528, filed May 17, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to an endoscopic instrument capable of being introduced into the human body through a forceps channel of an endoscope and used for medical treatment.
Conventionally, there is an endoscopic instrument 110 that comprises an elongated insert section 102 capable of being passed through a forceps channel 100 of an endoscope 101, a treatment section 104 attached to the distal end of the insert section 102, and an operating section 106 on the proximal end side of the insert section 102, as shown in FIG. 23. A desired treatment is conducted as the distal treatment section 104 is operated by pushing or pulling an operating wire, which is movably passed through the insert section 102, by means of the operating section 106. In the insert section 102 of the endoscopic instrument 110, as shown in FIG. 24, for example, a plastic tube 112 is located in a coil 108 that is formed of an element wire having a circular cross section, and a pair of operating wires 114,115 are passed through the tube 112 (cf. PCT National Publication No. 9-507420 (Symbiosis) or U.S. Pat. No. 5,133,727 (Symbiosis)).
In some endoscopic instruments such as biopsy forceps in which the distal treatment section 104 requires a force in carrying out treatment, a force of 10 kgf or more may be applied to the operating section 106 on the proximal end side. In this case, a similar force acts on the operating wires 114,115 that are passed through the coil 108 of the insert section 102. In the endoscopic instrument (see FIG. 24) having the construction described in PCT National Publication No. 9-507420 or U.S. Pat. No. 5,133,727, therefore, the force that is directed toward the center of the curvature acts on the operating wires 114, 115 when the operating section 106 is operated with the endoscope 101 curved, as shown in FIG. 23. As shown in FIGS. 24 and 25, moreover, the plastic tube 112, which is designed to smoothen the slide of the wires 114, 115, bites into the grooves 120 between the element wires of the coil 108, so that the force of the operating section 106 cannot be efficiently transmitted to the distal treatment section. In this case, the wires 114, 115 and the tube 112 are not fixed. Since the sliding resistance between the coil 108 and the tube 112 is higher than the resistance between the tube 112 and the wires 114,115, however, the wires 114,115 and the tube 112 move as one body in the coil 108 when the wires 114,115 are slid. If the movement of the plastic tube 112 is prevented, therefore, the force that is transmitted to the operating wires 114,115 attenuates.
The object of the present invention is to provide an endoscopic instrument capable of efficiently transmitting an operating force to a treatment section without being influenced by the curved state of an endoscope.
The above object of the present invention is achieved by the following endoscopic instrument. The endoscopic instrument according to the invention comprises a flexible insert section capable of being passed through a forceps channel of an endoscope, an operating wire located in a bore of the insert section and movable in the axial direction of the insert section, an operating section connected to the proximal end side of the insert section and used to move the operating wire forward and backward, and a treatment section attached to the distal end of the insert section and adapted to be operated as the operating wire is moved forward and backward. The operating wire is composed of at least one wire member, a resin member is located on or adhered to at least a part of the outer surface of the operating wire, at least the inner surface of the insert section is formed of a metallic coil, and a micro-flat portion is provided at least on that surface portion of an element wire of the coil which faces the operating wire.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.